This invention relates generally to an air vent damper apparatus for controlling airflow into the passenger compartment of an automotive vehicle.
Automotive vehicle air conditioning and ventilation systems include air vent control assemblies that vehicle occupants can use to control the amount of air flowing into a vehicle passenger compartment as well as the direction of airflow. Some air vent control assemblies include damper doors that are pivotally supported near the exit or exhaust end of air passages and that provide fluid communication between air sources and passenger compartments. Such assemblies may also include one or more air louvers that are pivotable to direct airflow from air passages into passenger compartments. It is desirable for such a control assembly to include a structure or structures that seal off or severely limit the amount of air that is allowed to leak around a perimeter of the damper door when the door is in a closed position. It is also desirable that the damper door in such a system be configured to impart as little turbulence as possible to airflow through the air passage when the doors are out of their closed positions.
One example of such an air vent control assembly is found in the Audi A6. The Audi control assembly includes a gasket-ringed damper door pivotally supported within an air passage of generally rectangular cross-section. The damper door rotates between a closed position in which the door blocks airflow through the air passage and a fully open position in which the door presents minimum obstruction to airflow through the air passage. In the closed position the edges of the damper door engage door stop surfaces in the form of ribs protruding inward from sidewalls of the air passage. The ribs and the door cooperate to more effectively shut-off the flow of air. The damper door may also be set at intermediate positions between closed and fully open to meter the amount of airflow through the air passage.
One of the door stop surfaces in the Audi system is positioned and shaped to engage an inner surface of the damper door along one side edge of the damper door when the damper door is in the closed position. The other stop surface is positioned and shaped to engage an outer surface of the damper door along a side edge of the damper door opposite the one side edge when the damper door is in the closed position. The door stop surfaces are shaped to complement and lie flat against the respective damper door surfaces that they engage. This reduces airflow between the interior surface of the air passage and the lateral edges of the door when the door is in the closed position.
One of the door stop surfaces of the Audi vent control assembly is defined by an offset formed in the air passage. It is desirable to mold stop surfaces by forming an offset in the air passage because it is considerably more difficult to mold ribs that extend inward from interior surfaces of a closed tube.
The Audi vent control assembly also includes a plurality of air louvers pivotally supported in the air passage adjacent an exit end of the air passage. The air louvers are operatively interconnected to pivot together and remain parallel to one another to direct air flowing from the exit end of the air passage. Without the air louvers, air vent damper assemblies of the type installed in the Audi A6 would only be able to control volume of airflow and would be unable to change the direction of air exiting the air passage.
Other vent control assemblies are also known to employ damper door edge gaskets to seal damper doors against inner air passage walls. Edge gaskets of this type are typically made of rubber, foam or other suitably soft elastomeric polymeric materials and are supported around the outer edge of a damper door. Problematically, when a damper door with an edge gasket is out of its closed position, the presence of the edge gasket tends to increase turbulence in the passing air and causes a pressure drop across the portion of the air passage that contains the damper door.
An air vent damper assembly for controlling air flow into the passenger compartment of an automotive vehicle. The assembly includes a gasketless damper door pivotally supported in an air passage for rotation about a door axis between a closed position in which the door blocks airflow through the air passage and a fully open position in which the door presents minimum obstruction to airflow through the air passage. The damper door is positionable at intermediate positions between closed and fully open to meter the amount of airflow through the air passage.
Unlike the prior art, the damper door is configured and positioned to direct air flowing from the exit end of the air passage when the damper door is out of the closed position. Configuring a single gasketless door to alternately shut off and direct air flowing from the air passage precludes the need for louvers to be added downstream from the door for the purpose of directing air.
According to another aspect of the invention, two elongated door stop surfaces extend perpendicularly inward from respective opposing side walls of an interior surface of the air passage. One of the door stop surfaces is positioned and shaped to engage an inner surface of the damper door along one side edge of the damper door when the damper door is in the closed position. The other of the two door stop surfaces is positioned and shaped to engage an outer surface of the damper door along a side edge of the damper door opposite the one side edge when the damper door is in the closed position. The door stop surfaces are shaped to complement and lie flat against the respective damper door surfaces that they engage to reduce airflow between the interior surface of the air passage and the lateral edges of the door when the door is in the closed position. The complementary shapes of the interfacing door surfaces and stop surface precludes the need to include a sealing gasket.
According to another aspect of the invention the air vent damper assembly is adapted to provide an angled air passage in which the exit end of the air passage is angled relative to the rest of the air passage and includes an elbow at the point of directional change. The damper door axis is disposed at the elbow and the leading panel of the damper door is oriented relative to the trailing panel at an angle approximating that of the angle measured between the exit end of the air passage and the rest of the air passage.
According to another aspect of the invention a louver is supported on the damper door and is configured to pivot with the damper door. The louver cooperates with the damper door and amplifies the effectiveness of the damper door in directing air flowing from the exit end of the air passage when the damper door is out of the closed position.
According to another aspect of the invention the louver is connected to a trailing panel of the damper door by upper and lower horizontal ribs. The louver, ribs and trailing panel define an upright, rigid rectangular box-shaped air channel.
According to another aspect of the invention the assembly includes an occupant-operable mechanical interface configured to allow a vehicle occupant to pivot the damper door between the closed and fully open positions. The interface allows damper door position control without direct damper door manipulation.
According to another aspect of the invention the mechanical interface includes a bushing positioned and configured to provide sufficient friction to prevent uncommanded movement of the damper. The bushing preferably comprises an acetal resin because of its characteristic resistance to creep.
According to another aspect of the invention the lever is supported on the air passage for pivotal motion about a thumbwheel axis and the lever includes a cylindrical axial extension having an outer cylindrical surface concentrically disposed around the thumbwheel axis. The bushing is a ring-type bushing slidably supported around the outer cylindrical surface of the cylindrical axial extension and is fixed against rotation relative to the air passage. The bushing is configured to permit pivotal movement of the lever within the bushing while dampening lever motion by maintaining radially inward pressure on the outer cylindrical surface of the lever. The bushing may be a spring bushing configured to maintain a generally constant amount of constricting radially inward force on the outer cylindrical surface of the cylindrical axial extension. The spring bushing includes a lobe formed radially outwardly at one point along the circumference of a ring portion of the bushing. The lobe is configured to allow the ring portion of the bushing to expand radially without plastically deforming and to enable the ring portion to maintain a generally constant radially inwardly directed force on the outer cylindrical surface of the cylindrical axial extension.
According to another aspect of the invention the mechanical interface includes an over-center lock. The over-center lock holds the damper door firmly in the closed position while allowing an operator to overcome the lock to open the door.